Finding the Third Proportional to 91.38 and 139.88

Step by Step Solution

1. Step 1: Write the proportion equation
   91.38 : 139.88 = 139.88 : x
2. Step 2: Convert to fraction form
   91.38/139.88 = 139.88/x
3. Step 3: Cross multiply
   91.38x = 139.88 × 139.88
4. Step 4: Simplify right side
   91.38x = 19,565.02
5. Step 5: Solve for x
   x = 19,565.02/91.38
6. Step 6: Final answer
   x = 214.12